1. Field of the Invention
The present invention relates to a connector which is structured by assembling a terminal member to a connector housing, and which connects with another connector.
2. Description of the Related Art
A connector has been structured by assembling terminal members, which are formed of a conductive metallic material, into terminal holes formed in a connector housing, which is formed of an insulative resin material. This connector is connected to a similarly structured other connector for putting the terminal members into states of conductive connection with terminal members of the other connector, such that this state is maintained. The terminal members are assembled to the connector housing such that the terminal members will not fall out from the terminal holes when disengaged from or engaged with the terminal members of the other connector.
As structures for assembling such a terminal member to a connector housing, a terminal lance structure and a housing lance structure are known. A terminal lance structure engages an engaging pawl provided at the terminal member with an engaging portion (a hole, a step portion or the like) formed inside the terminal hole of the connector housing. The housing lance structure engages an engaging pawl provided inside the terminal hole with a hole portion formed through a sleeve wall of a sleeve-like portion of the terminal member.
In a terminal lance structure, a portion of a sleeve wall of the terminal member, which is made of metal, curves out at an angle so as to protrude outward and form the engaging pawl. When the terminal member is being inserted into the terminal hole, this engaging pawl deforms to the sleeve wall side thereof and slides against a hole wall of the terminal hole to allow insertion. When the engaging pawl has passed the engaging portion of the connector housing, the engaging pawl is projected away from the sleeve wall by restoring force of the engaging pawl. Thus, engagement of the engaging pawl with the engaging portion is possible. Hence, the terminal member which has been inserted into the terminal hole is prevented from falling out of the terminal hole.
However, with a terminal lance structure as described above, because the engaging pawl is structured by a portion of the sleeve wall of the terminal member acting as a cantilevered metal piece, the engaging pawl may plastically deform when the terminal member is inserted into the terminal hole. Thus, restoring force may not be sufficient and it may not be possible to ensure an amount of engagement with the engaging portion. An inadequate engaging amount may result in the terminal member falling out from the terminal hole in accordance with connections of the terminal member to other terminal members.
On the other hand, in a housing lance structure, a taper-form engaging pawl is formed at a plate spring piece, which is integrally provided extending from the connector housing in the terminal hole. When the terminal member is inserted into the terminal hole and engages with a taper face of the engaging pawl, the plate spring piece deforms to allow the insertion. Then, when the hole portion of the terminal member reaches a region at which the engaging pawl is provided, the engaging pawl is moved into the hole portion by restoring force of the plate spring piece. Thus, the engaging pawl can be engaged with the hole portion. Hence, the terminal member which has been inserted into the terminal hole is prevented from falling out of the terminal hole.
More specifically, as is shown in FIG. 5, a plate spring piece 54, with length in an axial direction of a terminal hole 52 in a connector housing 50, is integrally provided in the terminal hole 52. The plate spring piece 54 has a cantilever structure, of which an end portion at a side from which an unillustrated terminal member is to be inserted is supported at the connector housing 50. An engaging pawl 56 is provided protruding from a vicinity of a free end of the plate spring piece 54. When the terminal member engages with a taper face 56A of the engaging pawl 56, the plate spring piece 54 bends downward, as shown by the broken lines in FIG. 5, such that insertion of the terminal member into the terminal hole 52 is allowed. Hence, because the plate spring piece 54 which is provided integrally with the connector housing 50 is made of resin, the plate spring piece 54 consistently restores without plastically deforming, and the engaging pawl 56 can be reliably moved into a hole portion of the terminal member. Thus, in regard to characteristics of retention of terminal members in connector housings, the housing lance structure has higher reliability than the terminal lance structure.
Meanwhile, there have been calls for reductions in size of connectors, that is, of connector housings. In particular, there have been strengthening calls for reductions in size of connectors that are employed in vehicles such as cars and the like.
However, with a connector featuring the housing lance structure as described above, it is not possible to reduce thickness of the plate spring piece, because strength of the plate spring piece must be maintained. That is, it is not possible to reduce space in the terminal hole 52 that is occupied by the plate spring piece, including space that is occupied by the plate spring piece in the deformed position (a lance space for engaging the terminal member with the engaging pawl). Thus, there has been a limit on reductions in size of connectors.
Furthermore, in the above-described housing lance structure, the plate spring piece has a cantilever structure, and it is necessary to specify respective gaps between the plate spring piece and two side walls of the terminal hole. Therefore, structure of a mold at a time of molding, that is, a die drawing structure, is complicated, and reductions in size are even more difficult in regard to maintaining strength and spacing of the mold (and of insert pieces thereof).